Polyethylene and polypropylene block copolymers

ABSTRACT

A semicrystalline multiblock copolymer includes alternating blocks of semicrystalline isotactic polypropylene (iPP) and semicrystalline polyethylene (PE), having a block arrangement according to formula (I):
 
(iPP w ) p (PE x )(iPP y ) m (PE z ) n    (I),
 
wherein p is 0 or 1; m is 0 or 1; n is 0 or 1; the sum of p, m, and n is 1, 2, or 3; and the sum of w, x, y, and z is greater than or equal to 40 kg/mol, with the provisos that: when m and n are 0, the sum of w and x is greater than or equal to 140 kg/mol; and when p and n are 0, the sum of y and x is greater than or equal to 140 kg/mol. Related compositions and methods are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase entry under Section 371 ofInternational Application No. PCT/US2017/034735, filed May 26, 2017,which published as WO 2017/205774 A1, which claims priority to U.S.Provisional Patent Application No. 62/342,583, filed May 27, 2016, andto U.S. Provisional Patent Application No. 62/421,680, filed Nov. 14,2016. The entire disclosures of each of the prior applications arehereby incorporated by reference herein in their entirety.

GOVERNMENT FUNDING

This invention was made with Government support under Grant NumberCHE-1413862 awarded by the National Science Foundation (NSF). The UnitedStates Government has certain rights in this invention.

FIELD OF THE INVENTION

This invention relates to, inter alia, polyethylene and polypropyleneblock copolymers, and to use of the block copolymers in adhering and/orcompatibilizing polyethylene and polypropylene.

BACKGROUND

Polyethylene (PE) and isotactic polypropylene (iPP) are the two mostabundantly produced plastics worldwide. Over 70 million and 50 millionmetric tons of PE and iPP, respectively, are produced annually. The vastmajority of polyethylene (PE) and isotactic polypropylene (iPP) areprepared using heterogeneous chromium and titanium catalysts.Heterogeneous olefin polymerization catalysts have a multitude of activesites, each with their own reactivity differences which give rise topolymers of different molecular weights, molecular weight distributions,and microstructures. In the case of PE and iPP, these differences andtheir phase separation inhibit interfacial adhesion and erode themechanical properties of melt blends, thereby significantly encumberingthe reusability of PE and iPP.

Only about 5% of the value of PE and iPP is retained when recycled,typically into lower-value products as a result of sorting expenses anddegraded physical properties, ultimately hindering the sustainablere-use of plastic. Since PE and iPP are immensely important economically(ca.>$200 billion in annual sales, worldwide) any new strategy thatallows these materials to be adhered and/or combined into compositeswill have significant potential to impact sustainability and theeconomy.

Despite many desirable physical properties of each plastic, adhering PEand iPP presents significant difficulties. Achieving adhesion generallyrequires use of PE and iPP produced by homogenous catalysts (less than10% of production), or use of energy intensive and/or expensive surfacefunctionalization. Compatibilizers open opportunities for upcyclingrecovered PE/iPP into equal or higher value materials with lower sortingcosts. However, strategies to compatibilize iPP and PE rely on theaddition of large amounts (usually at least 10 weight percent (wt %)) ofadditives, typically amorphous polymers. Since PE and iPP are immenselyimportant economically (ca.>$200 billion in annual sales, worldwide),strategies to combine these materials may have significant potential toimpact sustainability and the economy.

Thus, a need exists for technology that allows for the improvedadherence or compatibilization of PE and iPP.

While certain aspects of conventional technologies have been discussedto facilitate disclosure of the invention, Applicant in no way disclaimsthese technical aspects, and it is contemplated that the claimedinvention may encompass one or more of the conventional technicalaspects discussed herein.

In this specification, where a document, act or item of knowledge isreferred to or discussed, this reference or discussion is not anadmission that the document, act or item of knowledge or any combinationthereof was, at the priority date, publicly available, known to thepublic, part of common general knowledge, or otherwise constitutes priorart under the applicable statutory provisions; or is known to berelevant to an attempt to solve any problem with which thisspecification is concerned.

SUMMARY OF THE INVENTION

Briefly, the present invention satisfies the need for technology thatallows for the improved adherence or compatibilization of PE and iPP. Inparticular, the invention provides block polymers of PE and iPP that areuseful in, inter alia, adhering and/or compatibilizing/blending PE andiPP.

Embodiments of the invention may address one or more of the problems anddeficiencies discussed above. However, it is contemplated that theinvention may prove useful in addressing other problems and deficienciesin a number of technical areas. Therefore, the claimed invention shouldnot necessarily be construed as limited to addressing any of theparticular problems or deficiencies discussed herein.

Certain embodiments of the presently-disclosed block copolymers andrelated compositions and methods have several features, no single one ofwhich is solely responsible for their desirable attributes. Withoutlimiting the scope of the copolymers, compositions, and methods asdefined by the claims that follow, their more prominent features willnow be discussed briefly. After considering this discussion, andparticularly after reading the section of this specification entitled“Detailed Description of the Invention,” one will understand how thefeatures of the various embodiments disclosed herein provide a number ofadvantages over the current state of the art. These advantages mayinclude, without limitation, the provision of new block copolymers thatprovide for improved adherence and/or blending of PE and iPP, and thatallow for PE and iPP compositions (including films and blends) havingimproved properties such as, e.g., improved strength, mechanicaltoughness, and/or morphology.

In a first aspect, the invention provides a semicrystalline multiblockcopolymer comprising alternating blocks of semicrystalline isotacticpolypropylene (iPP) and semicrystalline polyethylene (PE), having ablock arrangement according to formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n)   (I),whereinp is 0 or 1;m is 0 or 1;n is 0 or 1;the sum of p, m, and n is 1, 2, or 3; andthe sum of w, x, y, and z is greater than or equal to 40 kg/mol, withthe provisos that:

when m and n are 0, the sum of w and x is greater than or equal to 140kg/mol; and

when p and n are 0, the sum of y and x is greater than or equal to 140kg/mol.

In a second aspect, the invention provides an adhesion layer comprisingthe semicrystalline multiblock copolymer according to the first aspectof the invention.

In a third aspect, the invention provides a multi-layer film or sheetcomprising:

-   -   a first layer comprising polyethylene;    -   a second layer comprising polypropylene; and    -   an adhesion layer comprising the semicrystalline multiblock        copolymer according to the first aspect of the invention,        wherein the adhesion layer is disposed between the first layer        and the second layer, and is in direct contact with the first        layer and the second layer.

In a fourth aspect, the invention provides a method of adhering a firstlayer comprising polyethylene and a second layer comprisingpolypropylene, the method comprising: contacting the first layer and thesecond layer with an adhesive composition comprising a semicrystallinemultiblock copolymer according to the first aspect of the invention.

In a fifth aspect, the invention provides a blended compositioncomprising polypropylene, polyethylene, and a semicrystalline multiblockcopolymer according to the first aspect of the invention.

In a sixth aspect, the invention provides a process for forming thesemicrystalline multiblock copolymer according to the first aspect ofthe invention, said process comprising:

-   -   in a reactor, in a non-polar, non-protic solvent, contacting        propylene monomers with a catalyst, thereby forming an iPP        block;    -   introducing ethylene monomers to the reactor, thereby forming a        PE block covalently bonded to the iPP block, thus forming a        semicrystalline diblock copolymer; and    -   optionally, performing one or more additional steps of        introducing to the reactor propylene and/or ethylene monomers,        thus forming a semicrystalline multiblock copolymer having        additional blocks.

These and other objects, features, and advantages of this invention willbecome apparent from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures. The depicted figures serve to illustratevarious embodiments of the invention. However, the invention is notlimited to the precise arrangements and instrumentalities of theembodiments depicted in the drawings.

FIGS. 1A and 1B are DSC curves showing melting temperatures andcrystallization temperatures, respectively, for multiblock copolymersaccording to certain embodiments of the invention.

FIGS. 2A-E are charts showing GPC analysis of aliquots and final PE/iPPmultiblock copolymers according to certain embodiments of the invention.

FIG. 3A shows representative peel test results obtained as a function ofblock copolymer molecular architecture and molecular weight. FIGS. 3B-Ddepict proposed models to explain the adhesive difference betweenembodiments of (B) tetrablock, (C) high-M_(n) diblock, and (D) low-M_(n)diblock copolymers.

FIGS. 4A-B provide DSC curves of PE/iPP multiblock copolymer embodimentsand blends.

FIGS. 5A-F depict charts showing peel strength between differentcombinations of commercial PE and iPP bulk films with and without anembodiment of high molecular weight block copolymer adhesive(iPP₇₇PE₁₃₈).

FIGS. 6 A-C depict charts showing peel force of PE/iPP laminates with(6A) styrene/butadiene elastomer(polystyrene-block-polybutadiene-block-polystyrene, styrene 30 wt. %)obtained from Sigma-Aldrich (#432490), (6B) amorphous high molecularweight ethylene propylene random copolymer prepared using 1/B(C₆F₅)₃(M_(n)=314,900; Ð=1.29; E:P 3:2), and (6C) no adhesive layer in place ofthe iPP-b-PE block copolymers.

FIG. 7A provides linear dynamic mechanical spectroscopy measurements ofembodiments of diblock and tetrablock copolymers. FIG. 7B providesuniaxial tensile elongation of embodiments of bulk diblock andtetrablock copolymers.

FIGS. 8A-D depict peel force results for laminates different thicknessdiblock copolymer films, and corresponding SEM images.

FIGS. 9A-D are SEM images of embodiments of laminates.

FIG. 10 is a chart showing the effect of polypropylene and polyethyleneblock sizes (±10 kg/mol) of diblock copolymer films (˜100 μm thick) onPE/iPP laminate peel strength. Laminates were prepared as describedherein with Dow iPP (H314-02Z) and Dow HDPE (DMDA8904) and the blockcopolymers detailed below. Values are the mean of 6 samples and errorbars reflect±1 standard deviation.

FIGS. 11A-R show results of GPC analysis and adhesion testing withdiblock copolymers. In particular, depicted is: (11A-C) GPC analysis oflow M_(n) iPP diblock copolymers with increasing M_(n) of PE blocks and(11D-F) their representative peel forces of PE/block copolymer/iPPlaminates. (11G-I) GPC analysis of moderate M_(n) iPP diblock copolymerswith increasing M_(n) of PE blocks and (11J-L) their representative peelforces of PE/block copolymer/iPP laminates. (11M-O) GPC analysis of highM_(n) iPP diblock copolymers with increasing M_(n) of PE blocks and(11P-R) their representative peel forces of PE/block copolymer/iPPlaminates. Elongation of PE film is poor due to rectangular shapedspecimens rather than dogbone shaped which distribute stresses evenly.

FIGS. 12A-C show: TEM images of the morphology obtained from aheterogeneous grade polyolefin blend containing 70 wt % PE and 30 wt %iPP; consequences of adding 5 wt % of tetrablock PP₆₀PE₈₀PP₇₅PE₉₀ tothis mixture; ductility and strain testing results, respectively.

FIGS. 13A-E depict TEM images of a PE/iPP phase separated blend (70:30,PE:iPP) with no block copolymer additive (A-D), and droplet diameteranalysis and average diameter of 2.16 μm (E).

FIGS. 14A-E depict TEM images of a PE/iPP compatibilized blend (70:30,PE:iPP) with 5 wt % diblock copolymer (iPP₆₀PE₈₀) additive (A-D), anddroplet diameter analysis and average diameter of 0.85 μm (E).

FIGS. 15A-E depict TEM images of a PE/iPP compatibilized blend (70:30,PE:iPP) with 5 wt % triblock copolymer (iPP₆₀PE₈₀iPP₇₅) additive (A-D),and droplet diameter analysis and average diameter of 0.84 μm (E).

FIGS. 16A-E depict TEM images of a PE/iPP compatibilized blend (70:30,PE:iPP) with 5 wt % tetrablock copolymer (iPP₆₀PE₈₀iPP₇₅PE₉₀) additive(A-D), and droplet diameter analysis and average diameter of 0.55 μm(E).

FIGS. 17A-B depict SEM images of PE/iPP uncompatibilized blends (70:30,PE:iPP) after uniaxial tensile testing showing iPP droplet pullout.FIGS. 17C-D are SEM images of PE/iPP compatibilized blends (70:30,PE:iPP) with 5 wt % tetrablock copolymer (PP₆₀PE₈₀PP₇₅PE₉₀) afteruniaxial tensile testing showing smooth surface indicative of efficientstress transfer between phases.

FIGS. 18A-C depict results from compiled uniaxial tensile elongation ofHDPE/iPP blends with 1 wt % tetrablock compatibilizer, with 5 wt %tetrablock, and no compatibilizer. Ratios of HDPE:iPP were varied from(18A) 30:70, (18B) 50:50, and (18C) 70:30, the same as FIG. 12, but withthe low molecular weight tetrablock copolymer PP₃₆PE₂₀PP₃₄PE₂₄ (Entry 4,Table II). All materials were melt blended at 180° C., then processed bya twin-screw microcompounder at 190° C. and compression molded intotensile specimens at 180° C. according the above procedure. The sampleswere strained at a rate of 100%/min at 25° C.

FIGS. 19A-I provide compiled uniaxial tensile elongation of (19A) PE,(19B) iPP, and (19C) PE/iPP blend (70:30, PE:iPP). (19D) Compiled testsof PE/iPP blend with the addition of (19D) 5 wt % and (19G) 1 wt %diblock copolymer, (19E) 5 wt % and (19H) 1 wt % triblock copolymer,(19F) 5 wt % and (19I) 1 wt % tetrablock copolymer. Materials were meltblended at 180° C., then processed by a twin-screw microcompounder at190° C. and compression molded into tensile specimens at 180° C. Thesamples were strained at a rate of 100%/min at 25° C.

FIGS. 20A-C are charts summarizing tensile properties of 70:30(HDPE:iPP) blend embodiments with the indicated multiblock copolymersadded in 1 wt %, 0.5 wt %, and 0.2 wt %.

FIGS. 21A-E are charts summarizing tensile properties of 70:30(HDPE:iPP) blend embodiments with the indicated multiblock copolymersadded in 1 wt %.

FIGS. 22A-E are charts summarizing tensile properties of 70:30(HDPE:iPP) blend embodiments with the indicated multiblock copolymersadded in 0.5 wt %.

FIGS. 23A-E are charts summarizing tensile properties of 70:30(HDPE:iPP) blend embodiments with the indicated multiblock copolymersadded in 0.2 wt %.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to, inter alia, a semicrystalline PE/iPPmultiblock copolymer, to compositions comprising the copolymer, and torelated methods.

Aspects of the present invention and certain features, advantages, anddetails thereof are explained more fully below with reference to thenon-limiting embodiments discussed and illustrated in the accompanyingdrawings. Descriptions of well-known materials, fabrication tools,processing techniques, etc., are omitted so as to not unnecessarilyobscure the invention in detail. It should be understood, however, thatthe detailed description and the specific examples, while indicatingembodiments of the invention, are given by way of illustration only, andare not by way of limitation. Various substitutions, modifications,additions and/or arrangements within the spirit and/or scope of theunderlying inventive concepts will be apparent to those skilled in theart from this disclosure.

A discussed above, most PE and iPP are immiscible. Embodiments of theinventive multiblock copolymers discussed herein advantageously allowfor adherence of, and compatibilization and effective blending of thetwo plastics.

In one aspect, the invention provides a semicrystalline multiblockcopolymer comprising alternating blocks of semicrystalline isotacticpolypropylene (iPP) and semicrystalline polyethylene (PE), having ablock arrangement according to formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n)   (I),whereinp is 0 or 1;m is 0 or 1;n is 0 or 1;the sum of p, m, and n is 1, 2, or 3; andthe sum of w, x, y, and z is greater than or equal to 40 kg/mol, withthe provisos that:

when m and n are 0, the sum of w and x is greater than or equal to 140kg/mol; and

when p and n are 0, the sum of y and x is greater than or equal to 140kg/mol.

As indicated above, the inventive semicrystalline multiblock copolymercomprises alternative blocks of semicrystalline iPP and semicrystallinePE, and comprises a block arrangement of formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n). “Blocks” are chemicallydistinct regions or segments joined (covalently bonded) in a linearmanner, that is, end-to-end. The inventive copolymer is a multiblockcopolymer, i.e., it contains two or more blocks, and it issemicrystalline. The iPP and PE blocks within the inventive multiblockcopolymers are semicrystalline blocks. The term “semicrystalline” meansthat the copolymer or block being identified by the term has a firstorder transition or crystalline melting point (T_(m)) as determined bydifferential scanning calorimetry (DSC).

Without wishing to be held to any theory, it is believed thatembodiments of the inventive multiblock copolymer work as effectively asthey do due to the ability of the blocks to co-crystallize. This meansthat as long as the blocks are sufficiently crystalline toco-crystallize they will be effective. Thermal melting transitions,mentioned above, are a good measure of this in polymers. The descriptionof the nature of the multiblock copolymers and the blocks comprisedtherein as semicrystalline is not meant to imply that no transitionregion exists between blocks. As will be appreciated by persons havingordinary skill in the art, between alternating blocks, block copolymersoften comprise short transition regions (typically these regionsrepresent less than about 1 wt % of the entire multiblock copolymer, anddo not appear on NMR spectroscopy), that comprise both iPP and PErepeating units. Thus, in a multiblock copolymer having a blockarrangement of formula (I),(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n), transition regions mayoccur between the blocks (e.g., transition regions “b” may exist asfollows: (iPP_(w))_(p)b(PE_(x))b(iPP_(y))_(m)b(PE_(z))_(n)). Thetransition regions are typically non-crystalline, however, since thetransition between alternating blocks is sharp and the regions arecomparatively very small, the semicrystalline nature of the multiblockcopolymers is not materially affected. The block copolymers still have afirst order transition or crystalline melting point (T_(m)) asdetermined by DSC, and the short transition regions do not affect thefunction of the multiblock copolymers.

In some embodiments, the semicrystalline multiblock copolymer or blockhas a T_(m) of greater than 79° C. (e.g., greater than 79, 80, 81, 82,83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100,101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114,115, 116, 117, 118, 119, or 120° C.). In particular embodiments, thesemicrystalline multiblock copolymer or block has a T_(m) of greaterthan 100° C., or greater than 120° C. In some embodiments, thesemicrystalline multiblock copolymer or block has a T_(m) of from 80° C.to 165° C. (e.g., 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110,111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124,125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138,139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152,153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, or 165° C.),including any and all ranges and subranges therein (e.g., 100° C. to165° C., 110° C. to 150° C., 115° C. to 138° C., 120° C. to 134° C.,etc.).

Embodiments of the multiblock copolymer are linear multiblock copolymers(i.e., the arrangement of the blocks is linear).

In some references to block copolymers made herein and in theaccompanying drawings, iPP blocks may be referred to as PP blocks. Evenwhere the i is omitted, the blocks are isotactic polypropylene blocks.

There are four blocks depicted in formula (I): (1) (iPP_(w))_(p); (2)(PE_(x)); (3) (iPP_(y))_(m); and (4) (PE_(z))_(n). As indicated above,p, m, and n are independently 0 (i.e., the indicated block is absent) or1 (i.e., the indicated block is present). Thus, for example, when p is 1and m and n are 0, the inventive multiblock copolymer embodiment is ablock copolymer having a block arrangement of formula: iPP_(w)PE_(x).

In formula (I), w, x, y, and z are the number average molecular weights(M_(n)), in kg/mol, of the blocks (1), (2), (3), and (4), respectively.For example, a block copolymer of formula iPP₃₅PE₁₅iPP₃₁PE₂₀ is amultiblock copolymer having (and, in this case, consisting of) a blockarrangement of iPP_(w)PE_(x)iPP_(y)PE_(z), wherein w=35 kg/mol (i.e.,the first block (1) has a molecular weight of 35 kg/mol), x=15 kg/mol(i.e., the second block (2) has a molecular weight of 15 kg/mol), y=31kg/mol (i.e., the third block (3) has a molecular weight of 31 kg/mol),and z=20 kg/mol (i.e., the fourth block (4) has a molecular weight of 20kg/mol). As would be readily understood by a person having ordinaryskill in the art, where a block is absent, it will not have a molecularweight (e.g., for a block copolymer of formula iPP_(w)PE_(x), the third(3) and fourth (4) blocks are absent, i.e., m and n are 0, and thus yand z are also 0).

The sum of w, x, y, and z is at least 40 kg/mol. Thus, thesemicrystalline multiblock copolymer has a molecular weight of at least40 kg/mol.

In some embodiments, the semicrystalline multiblock copolymer has amolecular weight of at least 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104,105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132,133, 134, 135, 136, 137, 138, 139, or 140 kg/mol.

In some embodiments, the semicrystalline multiblock copolymer has amolecular weight of 40 to 1,000 kg/mol (e.g., 40, 50, 60, 70, 80, 90,100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230,240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370,380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510,520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650,660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790,800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930,940, 950, 960, 970, 980, 990, or 1000 kg/mol), including any and allranges and subranges therein. For example, in some embodiments, thesemicrystalline multiblock copolymer has a molecular weight of 40 to 500kg/mol (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105,106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133,134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147,148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161,162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175,176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189,190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203,204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217,218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231,232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245,246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259,260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273,274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287,288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301,302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315,316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329,330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343,344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357,358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371,372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385,386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399,400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413,414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427,428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441,442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455,456, 457, 458, 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469,470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483,484, 485, 486, 487, 488, 489, 490, 491, 492, 493, 494, 495, 496, 497,498, 499, or 500 kg/mol), including any and all ranges and subrangestherein (e.g., 70 to 500 kg/mol, 140 to 500 kg/mol, etc.).

In some embodiments, the inventive semicrystalline multiblock copolymercomprises a block arrangement according to one of formulae (Ia)-(Ig):iPP_(w)PE_(x)   (Ia).iPP_(w)PE_(x)iPP_(y)   (Ib)PE_(x)iPP_(y)PE_(z)   (Ic).iPP_(w)PE_(x)iPP_(y)PE_(z)   (Id).iPP_(w)PE_(x)iPP_(y)PE_(z)iPP_(w′)   (Ie)PE_(z),iPP_(w)PE_(x)iPP_(y)PE_(z′)   (If)iPP_(w)PE_(x)iPP_(y)PE_(z)iPP_(w′)PE_(z′)   (Ig).

In formulae (Ie) and (Ig), w′ is the molecular weight (M_(n)), inkg/mol, of the iPP block preceding it. In formulae (If) and (Ig), z′ isthe molecular weight (M_(n)), in kg/mol, of the PE block preceding it.

In some embodiments, the inventive semicrystalline multiblock copolymeris a copolymer according to formula (I) or one of formulae (Ia)-(Ig).

In some embodiments of the semicrystalline multiblock copolymer, each ofw, x, y, z, w′, and z′, where present, is independently 10 to 250 kg/mol(e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112,113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126,127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140,141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168,169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182,183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196,197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210,211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224,225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238,239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, or 250 kg/mol),including any and all ranges and subranges therein (e.g., 15 to 200kg/mol, 15 to 175 kg/mol, etc.).

In some embodiments, the semicrystalline multiblock copolymer is adiblock copolymer (i.e., consisting of two blocks), a triblock copolymer(i.e., consisting of three blocks), a tetrablock copolymer (i.e.,consisting of four blocks), a pentablock copolymer (i.e., consisting offive blocks), or a hexablock copolymer (i.e., consisting of six blocks).In some embodiments, the semicrystalline multiblock copolymer is of ahigher order than a hexablock copolymer.

In some embodiments, the semicrystalline multiblock copolymer is adiblock copolymer having a block arrangement according to formula (Ia):iPP_(w)PE_(x)   (Ia).

In diblock embodiments, the semicrystalline multiblock copolymer has amolecular weight of greater than or equal to 140 kg/mol. As evidenced bythe Examples below, it has been found that such embodiments provide forunexpectedly better properties (e.g., in peel strength when used as anadhesive), as compared to lower molecular weight diblock embodiments.

In some embodiments, the inventive semicrystalline multiblock copolymerhas a molecular weight of greater than 140, 141, 142, 143, 144, 145,146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187,188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201,202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215,216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229,230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243,244, 245, 246, 247, 248, 249, or greater than 250 kg/mol.

In some diblock embodiments, the semicrystalline multiblock copolymer isof formula (Ia), wherein w is greater than 70 kg/mol, and x is greaterthan 70 kg/mol. In some embodiments, w and x are independently 71 to 250kg/mol (e.g., 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84,85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101,102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115,116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129,130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143,144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157,158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171,172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185,186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199,200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213,214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227,228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241,242, 243, 244, 245, 246, 247, 248, 249, or 250 kg/mol), including anyand all ranges and subranges therein.

In some embodiments of the inventive semicrystalline multiblockcopolymer having a block arrangement according to formula (I), at leastone of w, x, y, and z is greater than 100 kg/mol.

In some embodiments, the semicrystalline multiblock copolymer is atriblock copolymer having a block arrangement according to formula (Ib)or formula (Ic):iPP_(w)PE_(x)iPP_(y)   (Ib)PE_(x)iPP_(y)PE_(z)   (Ic).

In some embodiments, the inventive block copolymer is a triblockcopolymer of formula (Ib) or (Ic), wherein for formula (Ib), the sum ofw, x, and y is greater than or equal to 70 kg/mol, and for formula (Ic),the sum of x, y, and z is greater than or equal to 70 kg/mol.

In some embodiments where the inventive block copolymer is a triblockcopolymer, the triblock copolymer has a molecular weight of at least 71kg/mol, or at least 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84,85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101,102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115,116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129,130, 131, 132, 133, 134, 135, 136, 137, 138, 139, or 140 kg/mol.

In some embodiments, the semicrystalline multiblock copolymer is atetrablock copolymer having a block arrangement according to formula(Id):iPP_(w)PE_(x)iPP_(y)PE_(z),   (Id).

In some embodiments of the semicrystalline tetrablock copolymeraccording to formula (Id), w, x, y, and z are each independently greaterthan or equal to 15 kg/mol, or greater than or equal to 20 kg/mol.

In some embodiments of tetrablock copolymers according to formula (Id),the sum of w, x, y, and z is greater than or equal to 100 kg/mol.

In some embodiments, the semicrystalline multiblock copolymer accordingto the invention has one or more blocks in addition to those of formula(I). For example, in some embodiments, the inventive multiblockcopolymer is a pentablock copolymer or a hexablock copolymer.

The polydispersity index, Ð, is used as a measure of the broadness of amolecular weight distribution of a polymer, and is defined asÐ=M_(w)/M_(n), where M_(w) is weight-average molecular weight and M_(n)is number-average molecular weight. Dispersity (Ð) is a useful measureof the uniformity of polymers. The larger the polydispersity index, thebroader the molecular weight. Thus, a monodisperse polymer (such as aprotein) has dispersity Ð=1, and highly controlled synthetic polymershave a dispersity Ð˜1.

In some embodiments, the semicrystalline multiblock copolymer has apolydispersity index, Ð (where Ð=M_(w)/M_(n)) of 1.0 to 10 (e.g., 1.0,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8,3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2,5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6,6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0,8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4,9.5, 9.6, 9.7, 9.8, 9.9, or 10.0), including any and all ranges andsubranges therein (e.g., 1.0≥Ð≤3.0, 1.0≥Ð≤2.9, 1.1≥Ð≤2.5, 1.0≥Ð≤2.0,etc.).

In some embodiments, the ratio of the total amount of iPP to PE in thesemicrystalline multiblock copolymer is 25:75 (iPP/PE) to 75:25 (iPP/PE)(based on M_(n)), including any and all ranges and subranges therein.

In some embodiments, the total amount of iPP in the semicrystallinemultiblock copolymer is 25 to 75 wt % (based on M_(n)) (e.g., 25, 26,27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, or 75 wt %), includingany and all ranges and subranges therein.

In some embodiments, the total amount of PE in the semicrystallinemultiblock copolymer is 25 to 75 wt % (based on M_(n)) (e.g., 25, 26,27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, or 75 wt %), includingany and all ranges and subranges therein.

In a second aspect, the invention provides an adhesion layer comprisingthe semicrystalline multiblock copolymer according to the first aspectof the invention.

In a third aspect, the invention provides a multi-layer film or sheetcomprising:

-   -   a first layer comprising polyethylene;    -   a second layer comprising polypropylene; and    -   an adhesion layer comprising the semicrystalline multiblock        copolymer according to the first aspect of the invention,        wherein the adhesion layer is disposed between the first layer        and the second layer, and is in direct contact with the first        layer and the second layer.

In some embodiments of the multi-layer film or sheet, the polyethylenecomprises, or is selected from high density polyethylene (HDPE), linearlow-density polyethylene (LLDPE), ultra high molecular weightpolyethylene (UHMWPE), low density polyethylene (LDPE), very low densitypolyethylene (VLDPE), and polyethylene polyolefin block copolymer (e.g.,Engage, Affinity, INFUSE).

In some embodiments of the multi-layer film or sheet, the polypropylenein the second layer comprises, or is selected from the group consistingof: isotactic polypropylene (iPP), impact modified polypropylene,polypropylene fibers, and biaxially oriented polypropylene (BOPP).

In a fourth aspect, the invention provides a method of adhering a firstlayer comprising polyethylene and a second layer comprisingpolypropylene, the method comprising: contacting the first layer and thesecond layer with an adhesive composition comprising a semicrystallinemultiblock copolymer according to the first aspect of the invention.

In some embodiments, the adhesive composition is provided in the form ofa film or sheet.

Persons having ordinary skill in the art are familiar with varioustechniques for applying the adhesive composition, and any art-acceptablemethod can be used. In some embodiments, the adhesive composition isapplied to the first layer or the second layer by blow molding,electrospinning, melt extruding, injection molding, application throughsheer force, or solvent casting (e.g., spin-casting).

In a fifth aspect, the invention provides a blended compositioncomprising polypropylene, polyethylene, and a semicrystalline multiblockcopolymer according to the first aspect of the invention.

In some embodiments, the polypropylene, polyethylene, andsemicrystalline multiblock copolymer are present in a mixture having anaverage droplet diameter of less than 1 μm.

In some embodiments, the blended composition comprises 0.2 to 10 wt %(e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4,1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8,2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2,4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6,5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0,7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4,8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8,9.9, or 10.0 wt %) of the semicrystalline multiblock copolymer,including any and all ranges and subranges therein (e.g., 0.2 to 5.0 wt%, 0.2 to 4.5 wt %, etc.).

In some embodiments of the blended composition, the polyethylenecomprises, or is selected from high density polyethylene (HDPE), linearlow-density polyethylene (LLDPE), ultra high molecular weightpolyethylene (UHMWPE), low density polyethylene (LDPE), very low densitypolyethylene (VLDPE), and polyethylene polyolefin block copolymer (e.g.,Engage, Affinity, INFUSE).

In some embodiments of the blended composition, the polypropylenecomprises, or is selected from the group consisting of: isotacticpolypropylene (iPP), impact modified polypropylene, polypropylenefibers, and biaxially oriented polypropylene (BOPP).

In some embodiments, the ratio of the total amount of polyethylene (PE)to polypropylene (PP) in the blended composition, excluding the blockcopolymer, is 10:90 (PE/PP) to 90:10 (PE/PP) wt %, including any and allranges and subranges therein.

In some embodiments, the total amount of PE in the blended compositionis 10 to 90 wt % (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75,76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 wt %),including any and all ranges and subranges therein.

In some embodiments, the total amount of PP in the blended compositionis 10 to 90 wt % (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75,76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 wt %),including any and all ranges and subranges therein.

In a sixth aspect, the invention provides a process for forming thesemicrystalline multiblock copolymer according to the first aspect ofthe invention, said process comprising:

-   -   in a reactor, in a non-polar, non-protic solvent, contacting        propylene monomers with a catalyst, thereby forming an iPP        block;    -   introducing ethylene monomers to the reactor, thereby forming a        PE block covalently bonded to the iPP block, thus forming a        semicrystalline diblock copolymer; and    -   optionally, performing one or more additional steps of        introducing to the reactor propylene and/or ethylene monomers,        thus forming a semicrystalline multiblock copolymer having        additional blocks.

In some embodiments, the catalyst used in the inventive process is apyridylamidohafnium catalyst, for example, one that corresponds to thatdescribed in commonly-owned International Application No.PCT/US2008/003010, filed Mar. 7, 2008, which published as WO/2008/112133on Sep. 18, 2008.

In some embodiments, the solvent used in the process is selected fromtoluene, benzene, xylene, hexane, heptane, and methylene chloride. In aparticular embodiment, the solvent is toluene.

In some embodiments of the inventive process, the catalyst is thereaction product of a pyridylamidohafnium catalyst precursor and anactivator.

In some embodiments, the pyridylamidohafnium catalyst precursor is asdefined in PCT/US2008/003010. For example, in some embodiments, thepyridylamidohafnium catalyst precursor is a compound of formula (II)

whereinR²¹ and R^(21′) are independently selected from H and methyl;R²² and R^(22′) are independently selected from isopropyl andtert-butyl;R²³ is selected from H, isopropyl and tert-butyl; andR²⁴ and R^(24′) are independently selected from C₁-C₄ linear or branchedalkyl and benzyl.

In some embodiments, the pyridylamidohafnium catalyst precursor is:

In some embodiments, the activator is selected from methylaluminoxaneand B(C₆F₅)₃. In particular embodiments, the activator is B(C₆F₅)₃.

EXAMPLES

The invention will now be illustrated, but not limited, by reference tothe specific embodiments described in the following examples.

Materials and Methods

General Considerations

All manipulations of air- and/or water-sensitive compounds were carriedout under dry nitrogen using an MBraun Unilab drybox. ¹³C NMR spectra ofpolymers were recorded on a Varian Inova (500, 600 MHz) spectrometerequipped with a ¹H/BB switchable with Z-pulse field gradient probereferenced versus residual solvent signals. The polymer samples weredissolved in 1,1,2,2-tetrachloroethane-d₂ in a 5 mm O.D. tube, andspectra were recorded at 135° C. Molecular weights (M_(n) and M_(w)) andmolecular weight distributions (Ð) were determined by gel permeationchromatography (GPC). Analyses were performed using an Agilent PL-220equipped with a RI detector. The column set (three Agilent PL-Gel MixedB columns and one PL-Gel Mixed B guard column) was eluted with1,2,4-trichlorobenzene containing 0.01 wt %3,5-di-tert-butyl-4-hydroxytoluene (BHT) at 1.0 mL/min at 150° C. Datawere measured relative to a polyethylene calibration curve (Varian andPolymer Standards Service). Peak polymer melting (T_(m)) temperaturesand glass transition (T_(g)) temperatures were measured by differentialscanning calorimetry (DSC) using a Mettler Polymer DSC calorimeterequipped with an automated sampler. Analyses were performed in aluminumpans under nitrogen and data were collected from the second heating runat a heating rate of 10° C./min from 20 to 180° C. and cooled from 180to 20° C. at a cooling rate of 10° C./min. Compression molding wascarried out using a 4120 Hydraulic Unit Carver press and stainless steeldie molds. Mylar and Teflon protective sheets were obtained from Carverand American Durafilm, respectively. Uniaxial tensile elongation wascarried out using a Zwick/Roell Z010 testing system equipped with a 10kN load cell and analyzed using Zwick/Roell TestXpert II v.3.5 software.Melt blends were prepared using a vertical conical counter-rotating twinscrew batch compounder with a 2.5 mm diameter extrusion die and 5 gcapacity mixing chamber. All polymer processing was carried out onpristine materials (i.e. no BHT, other anti-oxidants, or additives wereadded). Further experimental details are provided below.

Materials

Toluene was purified over columns of alumina and copper (Q5) prior touse and degassed by bubbling a stream of nitrogen gas through thesolvent for 1 hour. Ethylene (Matheson, Matheson purity) and propylene(Airgas, polymer grade) were purified over columns of copper Q5 and 4 Åmolecular sieves. B(C₆F₅)₃ was obtained from TCI Chemicals and used asreceived. Pyridylamidohafnium catalyst (1):

was prepared according to the procedure set forth in commonly-ownedInternational Application No. PCT/US2008/003010.Diisobutylaluminumphenolate (DIBAP) was prepared by adding BHT (0.220 g,1.00 mmol, 1.00 equiv.) in toluene (2 mL) to Al(^(i)Bu)₃ (0.198 g, 1.00mmol, 1.00 equiv.) in toluene (2 mL) dropwise inside a glovebox andstored in a Teflon cap sealed vial (25). Polypropylene was obtained fromDow Chemical Company (H314-02Z; M_(n)=100 kg/mol; Ð=4.1; T_(m)=163° C.;MFI=2.0 g/10 min at 230° C. with 2.16 kg). HDPE was obtained from Dow(DMDA8904; M_(n)=22 kg/mol; Ð=3.8; T_(m)=131° C.; MFI=4.4 g/10 min at190° C. with 2.16 kg). Additional materials tested are shown anddescribed in Table I.

TABLE I M_(n) Ð T_(m) T_(c) MFI (kg/mol) M_(w)/M_(n) (° C.) (° C.) (g/10min) PE Grades J-rex HD KF 14 13.8 130 115 — 251A (HDPE) DOW 22 3.8 131116 4.4 (190° C.) DMDA8904 (HDPE) SigmaAldrich 15 2.2 129 112 12.0 (190°C.) (427985) (HDPE) DOW 955I 17 2.6 114 94 35 (190° C.) (LDPE) ExxonLL3003 16 6.3 126 108 3.2 (190° C.) (LLDPE) iPP Grades DOW H314-02Z 1004.1 163 117 2.0 (230° C.) SigmaAldrich 97 3.1 165 109 4.0 (230° C.)(427861)Synthesis of iPP-b-PE Semicrystalline Multiblock CopolymersGeneral Procedure

In a typical reaction, toluene (150 mL) was loaded into a 12 oz.Fischer-Porter bottle in a nitrogen-filled glove box. To this was added50 μmol of a 0.25M solution of DIBAP scavenger. In the glovebox, a vialwas charged with pyridylamidohafnium catalyst (1) of the appropriateamount indicated in Table II along with B(C₆F₅)₃ (1.00 equiv). Thisco-catalyst mixture was then dissolved in toluene from theFischer-Porter reactor and transferred via pipette to the Fischer-Porterbottle. The reaction vessel was sealed and removed from the glove box.The vessel weight was tared prior to charging propylene into the vesselto the amount indicated in Table II. The reaction was magneticallystirred for 90 minutes in a water bath at 22° C. to help dissipate heatfrom the exothermic reaction. The pressure gauge dropped to 0 atm within20 minutes for all reactions, but was continued to ensure completeconsumption of propylene. The reaction mixture became heterogeneous withfinely dispersed iPP particles precipitating from the yellow solution.The reactor head was then attached to a quick-connect valve routed to anitrogen tank and vacuum pump. The vessel was pressurized with nitrogen(1.5 atm) and evacuated under vacuum for 5 seconds before backfillingwith nitrogen. This was repeated for a total of three times beforeallowing the reaction to stir for an additional hour under nitrogen.While under a positive pressure of nitrogen a syringe with 18-gaugestainless steel needle (dried in an oven at 180° C. for 24 h) was usedto remove an aliquot of the reaction (˜5 mL) and quenched by adding toMeOH (10 mL), filtered, and dried for GPC analysis. The reaction vesselwas vented and charged with ethylene at the pressure indicated in TableII. The reaction vessel was stirred under ethylene for the reaction timeindicated prior to venting. During this time the block copolymer productbegan to rapidly precipitate from solution and it is desirable tomaintain adequate stirring during the ethylene polymerization for welldefined (low Ð) polymers. Mn values increased linearly as a function ofmonomer conversion. As evidenced by, e.g., entries 1 and 2 in Table II,the molecular weight (MW) of the ethylene block was controlled byvarying reaction time under a constant ethylene feed, whereas propyleneMWs were tuned by the monomer:catalyst ratio and full conversion. Ifmultiple blocks were prepared, the vessel was evacuated under vacuum andbackfilled with nitrogen three times as described before and stirred for60 minutes prior to introducing the next monomer. Upon completion of thereaction, the vessel was vented and acidic MeOH (5% HCl, 10 mL) wasinjected. The heterogeneous mixture was then poured into acidic MeOH(300 mL), stirred for at least 3 hours, vacuum filtered, and dried undervacuum at 60° C. All samples prepared in Table II were synthesized usingthis procedure. In Table II, “PP” represents iPP. Molecular weights(M_(n)) and dispersities (Ð=M_(w)/M_(n)) were determined usingsize-exclusion chromatography calibrated with polyethylene standards.

TABLE II Properties of Semicrystalline PE/iPP Block Copolymers. ProductCat. C₃H₆ P_(ethylene) t_(rxn)C₂H₄ Yield M_(n) (theo.) M_(n) (tot.) ÐT_(m) Entry (PP_(kDa)PE_(kDa)) (μmol) (g) (atm) (min) (g) (kg/mol)(kg/mol) (M_(w)/M_(n)) (° C.) 1 PP₇₁PE₁₃₇ 30 2.3 2.7 10 6.2 207 208 1.29133 2 PP₇₃PE₅₀ 30 2.3 2.7 5 3.9 130 123 1.29 131 3 PP₂₄PE₃₁ 75 1.5 2.0 33.3 44 55 1.32 132 4 PP₃₆PE₂₀PP₃₄PE₂₄ 25 1.0, 1.0 1.4, 1.4 4, 4 3.0 120113 1.38 124 5 PP₆₀PE₈₀PP₇₅PE₉₀ 30 2.0, 2.0 2.7, 2.7 4, 4 8.5 283 3061.29 126 Cat., catalyst; P_(ethylene), pressure of ethylene; t_(rxn),reaction time; M_(n), number-average molecular weight; theo.,theoretical; tot., total; M_(w), weight-average molecular weight; Ð,dispersity; T_(m), melting temperature.

Scheme 1 presents a simple schematic for the general synthesis describedabove used to make the examples listed in Table II.

Alternative, Simplified Procedure without Vacuum Pump

A large scale polymerization was carried out in similar ratios to entry1, Table II, above, but without the use of vacuum/nitrogen backfilling.Toluene (300 mL) was added to a 24 oz. Fischer-Porter bottle in anitrogen-filled glove box. DIBAP scavenger (75 μmol of 0.25M solution)was added. In a separate pyridylamidohafnium catalyst 1 (32 mg, 50 μmol)and B(C₆F₅)₃ (26 mg, 50 μmol, 1.00 equiv.) were weighed together andsubsequently dissolved by adding the toluene/DIBAP mixture to the vial,before transferring to the Fischer-Porter bottle. The reaction vesselwas sealed and charged with propylene gas (5.0 g) and stirred for 3h atroom temperature in a 22° C. water bath. Approximately 5 mL of thereaction mixture was removed using a syringe equipped with an 18-gaugeneedle and quenched by adding to MeOH (10 mL). The reaction vessel wasthen charged with ethylene gas (2.7 atm) and rapidly stirred for 10minutes. After this time, the reaction vessel was vented and quenchedwith the addition of acidic MeOH (5% HCl, 10 mL), precipitated intoacidic MeOH (300 mL), stirred for 3 hours, vacuum filtered, washed withMeOH (˜100 mL) and dried under vacuum at 60° C. overnight. The resultingpolymer (8.3 g, PP₇₇PE₁₃₈) had a T_(m) of 128° C., M_(n) (theo.) of 166kg/mol, M_(n) (tot.) of 215 kg/mol, and Ð=1.4. This alternativeprocedure may be more amenable to certain laboratory setups.

FIGS. 1A and 1B are DSC curves showing melting temperatures andcrystallization temperatures, respectively, for the multiblockcopolymers of Table II. Measurements were conducted between 20 and 180°C. at 10° C./min. Melting temperatures (T_(m)) were calculated accordingto the peak endotherm on the second heating cycle (FIG. 1A).Crystallization temperatures (T_(c)) were calculated according to thepeak exotherms of the first cooling cycle (FIG. 1B).

The single melting endotherms observed (FIG. 1A) are due to regio- andstereoerrors in the propylene block, which lower the T_(m) of the iPPhomopolymers to 134° C. (vs. ˜165° C. for perfect iPP) which is verysimilar to the T_(m) of the PE block (135° C.). This was confirmed byquantitative ¹³C NMR spectroscopy, which showed high stereoselectivityfor 1,2-insertion of polypropylene (m⁴=91%), regio-errors previouslyobserved with this class of catalysts were also detected. Importantly,the NMR spectra showed neither detectable vinylidene end-groups, whichwould arise from β-hydride elimination, nor peaks consistent with randomethylene-co-propylene segments; this confirms there is minimal taperingin the materials. Consistent with this reactivity, catalyst 1/B(C₆F₅)₃was capable of synthesizing PE/iPP tetrablock copolymers (entries 4 and5 in Table II). GPC analysis of aliquots taken after completeconsumption of the monomers showed that molecular weights increasedafter each monomer addition and molar mass dispersities remained low(FIGS. 2A-E), although some molecular weight broadening was observed dueto precipitation of the insoluble, semicrystalline polymer. FIGS. 2A-Eare charts showing GPC analysis of aliquots and final PE/iPP blockcopolymer products presented in Table II. Molecular weights andmolecular weight distributions (Ð) were analyzed using an Agilent PL-220equipped with a RI detector and three Agilent PL-Gel Mixed B columns andone PL-Gel Mixed B guard column. Samples were eluted with1,2,4-trichlorobenzene at 1.0 mL/min at 150° C. and measured relative toa polyethylene calibration curve.

Adhesion Studies

Owing to thermodynamic incompatibility, weak van der Waals interactions,and the accumulation of amorphous polymer at the junction between meltmolded laminates, most commercial grades of iPP and PE homopolymersdisplay poor interfacial adhesion.

Preparation of iPP and PE Films

Polymer pellets of Dow iPP (H314-02Z) or Dow HDPE (DMDA8904) werepressed in a Carver press between Mylar sheets at 180° C. for 5 minuteswith minimal pressure to create a coherent film which was subsequentlytrimmed to approximately 6 cm×10 cm and compression molded in a 6 cm×10cm×0.34 mm stainless steel die at 180° C. for 5 minutes under 70 atm ofpressure and cooled with water circulation (˜10° C./min). The filmsurfaces were subsequently wiped with a Kim-wipe soaked with CHCl₃ andair dried for 24 h.

Preparation of iPP-b-PE Adhesive

Block copolymer powder was pressed in a Carver press between protectivesheets (either Mylar or Teflon) at 180° C. for 5 minutes with minimalpressure to create a coherent film. The film was trimmed to ˜3 cm×˜10 cmand compression molded without a die at 180° C. for 5 minutes under 550atm of force and cooled with water circulation. The film was measured bycalipers to be between 95 and 115 μm thick and trimmed to 3 cm×10 cm.The film surfaces were subsequently wiped with a Kim-wipe soaked withCHCl₃ and air dried for 24 h.

Preparation of Laminate

HDPE film was placed in a 6 cm×10 cm×1 mm stainless steel die and theiPP-b-PE adhesive strip was placed carefully over the bottom half of theHDPE sheet. The iPP sheet was placed on top of the two, therebysandwiching the block copolymer film between the PE and iPP. Thetrilayer was pressed at 180° C. for 5 minutes under 70 atm of pressurebefore cooling with water circulation (˜10° C./min). Once at roomtemperature, the laminate was removed from the die and aged for 48hours. A crack was started at the interface of the top half, whichcontained no block copolymer adhesive. The 6 cm×10 cm laminate was thentrimmed into 6-14 individual 0.6 cm×6 cm rectangular adhesive samplesfor testing.

T-Peel Testing

A simple peel test was used to evaluate adhesion between heterogeneousgrade PE and iPP laminates with and without the presence of embodimentsof multiblock copolymers as an adhesive layer. Rectangular plaques ofbilayer (PE/iPP) and trilayer (with block copolymer film), after beingcompression molded in the melt, were pulled apart while monitoring thepeel strength (S, force/sample width). This test provides a facilemethod for comparing the interfacial strength between the molded films.

FIG. 3A shows representative peel test results obtained as a function ofblock copolymer molecular architecture and molecular weight. Resultsobtained from 100 μm thick block copolymer films are shown, but it isnoted that no thickness dependence was observed down to 5 μm solventcast films (see FIGS. 8A-D).

FIG. 8 shows: (8A) Peel force of PE/iPP laminates which contain a 5 μmthick film of high molecular weight diblock copolymer (PP₇₇PE₁₃₈),measured by (8C) SEM. (8B) Peel force of PE/iPP laminates which containa 10 m thick film of high molecular weight diblock copolymer(PP₇₇PE₁₃₈), measured by (8D) SEM. 5 m thick block copolymer films (8C)were prepared by dissolving 0.5 wt % PP₇₇PE₁₃₈ diblock copolymer inxylenes at 100° C. and then the hot solution (0.24 g) was transferred toa sheet of Dow iPP (H314-02Z) with an area of 6 cm×4 cm and solventevaporated. 10 μm thick block copolymer films (8D) were prepared by thesame procedure using a 1 wt % PP₇₇PE₁₃₈ solution in xylenes. SEM images(8C and 8D) where cryofractured in liquid nitrogen at various spots toverify the uniformity and thickness of the block copolymer layers; atleast two sheets were used for each thickness.

Returning to FIG. 3A, rectangular sheets (0.6 cm by 6 cm, 340 μm thick)of PE/iPP were laminated in the melt at 180° C. with and without PE/iPPblock copolymer layers (100 m thick) and pulled apart at 10 mm/min.Stars indicate that PE films break or deform rather than undergodelamination. Specimens were investigated with SEM imaging after testing(FIGS. 9A-D).

FIGS. 9A-D are SEM images of laminates after testing showing the smoothsurface of the (9A) PE film and (9B) iPP film, consistent with lowadhesive force, no block copolymer adhesive, and little polymer chaindeformation. (9C) shows the surface of the PE film after testing with alow molecular weight (PP₂₄PE₃₂) diblock copolymer while (9D) shows theiPP film. The zoomed inset of (9C) suggests samples containing a blockcopolymer layer have deformed (stretched) in agreement with the moderatepeel strength required to stretch the polymer chains. It is unclear fromthese studies if the deformed material is block copolymer or bulkpolyolefin film.

Returning to FIG. 3, laminates without block copolymer peel aparteasily, (S<0.5 N/mm). Incorporation of the semicrystalline iPP₂₄PE₃₁ andiPP₇₃PE₅₀ diblock copolymers increases the peel strength to S≈1 N/mm andS≈3 N/mm, respectively. Increasing the molecular weight of both blocksbeyond a threshold value leads to a dramatic change in the failuremechanism from adhesive failure (low molecular weights) to cohesivefailure (fracture, S>6 N/mm) of the PE homopolymer film above about 75kg/mol as shown in FIG. 3A (see also, FIG. 10 and FIGS. 11A-R). Theinterfacial strength between the diblock and homopolymer films isdependent on the block sizes due to two factors. The block copolymeracts as a surfactant, eliminating the thermodynamic driving force foramorphous materials to localize at the interface between block copolymerand iPP and PE film junctions. In some respects, the block copolymeracts as a type of macromolecular welding flux material. Secondly,increasing the overall block size enhances interpenetration and thenumber of entanglements between the chemically identical blocks andhomopolymers chains in the melt state. Moreover, we anticipate athreshold molecular weight beyond which the polymer block will be ableto bridge the amorphous layers associated with the lamellar morphologyof semicrystalline polymers such as iPP and PE leading toco-crystallization along the film interfaces as shown in FIG. 3C andFIGS. 4A-B, which provide DSC curves of PE/iPP multiblock copolymers andblends from Table II. As can be seen from FIGS. 4A and 4B, iPPhomopolymer produced by catalysts 1/B(C₆F₅)₃ and as a blend (1:1) withcommercial iPP showing a single melting Materials were melt blended at190° C. without endotherm and crystallization exotherm indicating regioand stereo defects of the iPP block are not numerous enough to inhibitcocrystallization. Measurements were conducted between 20 and 180° C. at10° C./min. Melting temperatures (T_(m)) were calculated according tothe peak endotherm on the second heating cycle (FIG. 4A).Crystallization temperatures (T_(c)) were calculated according to thepeak exotherms on the first cooling cycle (FIG. 4B).

Without being bound by theory, FIGS. 3B-D depict proposed models toexplain the adhesive difference between embodiments of (B) tetrablock,(C) high-M_(n) diblock, and (D) low-M_(n) diblock copolymers. Blockcopolymers are in multiple lamellae (40-70 nm); the first layer isshown. Lower molecular weight diblocks are less capable of reaching thehomopolymers crystalline lamellae (see FIG. 3D) and are prone to chainpull-out, resulting in lower adhesive strength. The welding effect wasobserved in various polyolefin materials (see FIGS. 5A-F) and only withsemi-crystalline block polymer adhesives (see FIGS. 6 A-C).

FIGS. 5A-F depict charts showing peel strength between differentcombinations of commercial PE and iPP bulk films with and without highmolecular weight block copolymer adhesive (iPP₇₇PE₁₃₈). Films wereprepared according the above procedure. In all samples the PE bulk film,regardless of PE density, yielded or broke demonstrating the adhesionstrength of the interface surpassed the bulk tear strength in allsamples (≥6).

FIGS. 6 A-C depict charts showing peel force of PE/iPP laminates with(6A) styrene/butadiene elastomer(polystyrene-block-polybutadiene-block-polystyrene, styrene 30 wt. %)obtained from Sigma-Aldrich (#432490), (6B) amorphous high molecularweight ethylene propylene random copolymer prepared using 1/B(C₆F₅)₃(M_(n)=314,900; Ð=1.29; E:P 3:2), and (6C) no adhesive layer in place ofthe iPP-b-PE block copolymers. PE/iPP films were Dow iPP (H314-02Z) andDow HDPE (DMDA8904).

Returning to FIG. 3, the PP₃₆PE₂₀PP₃₄PE₂₄ tetrablock copolymer alsoexhibits extraordinary adhesive strength evidenced by cohesive failure(FIG. 3B), seemingly contradicting the above molecular weight findingsfor diblock copolymers, as all the blocks are well below the thresholdmolecular weight for cohesive failure with diblocks. We invoke adifferent mechanism for this result. A tetrablock molecular architectureensures that half the iPP and PE blocks are flanked by thethermodynamically incompatible counterparts. This implies thatinterfacial mixing during melt compression produces entangled loops thateffectively stitch together the homopolymers and block copolymer filmsupon crystallization when the laminates are cooled as illustrated inFIG. 3B. Similar arguments account for the enhanced toughness of bulkmultiblock versus triblock polymers. Consistent with this line ofreasoning, the PP₃₆PE₂₀PP₃₄PE₂₄ tetrablock copolymer is microphaseseparated up to 260° C. as shown by rheological measurements (see FIGS.7A-B).

FIG. 7A provides linear dynamic mechanical spectroscopy measurements ofdiblock (iPP₇₃PE₅₀) and tetrablock (iPP₃₆PE₂₀iPP₃₄PE₂₄) copolymers usedin FIG. 3A demonstrating that these materials are microphase separatedover the range of temperatures employed in this work. Rheologyexperiments were carried out on an ARES rheometer with a 25-mm parallelplate geometry and a gap of 0.8 mm. Data were collected at individualtemperatures between 180° C. to 260° C. over a frequency range of 0.01to 100 rad/s. The master curves were obtained by shifting the isothermalfrequency data along the frequency axis by a_(T). The low frequencyresponses G′˜ω^(a) and G″˜ω^(b), where a<1 and b<1, are indicative of anordered state. FIG. 7B provides uniaxial tensile elongation of bulkdiblock (iPP₇₃PE₅₀) and tetrablock (iPP₃₆PE₂₀iPP₃₄PE₂₄) materialsshowing similar ductile mechanical responses. Block copolymers werecompression molded at 180° C. to form a 0.2 mm thin film then cooledwith water circulation. Tensile samples were punched into dogbone shapedsamples with a gauge width of 3 mm and gauge length of 10 mm. At least 5tensile tests were conducted at room temperature with an extension rateof 5 mm/min using a Shimadzu AGX tensile tester.

Melt Blend Studies

Challenges of recycling mixed polyolefin municipal waste (typically70:30 PE:iPP) are in part due to interfacial phase separation leading topoor mechanical properties. Since specialty grades of PE and iPP can beblended to improve impact and crack resistance, the effectivecompatibilization of heterogeneous grade polyolefins may allow anupcycling of plastic wastes into higher value materials.

Blend Preparation

Polymer pellets of Dow iPP (H314-02Z, 1.2 g) and Dow HDPE (DMDA8904, 2.8g), and block copolymer powder (200 mg or 40 mg) were combined andpressed at 180° C. for 5 minutes with minimal pressure to create acoherent film. The film was fed into a twin-screw microcompounder at190° C. with a steady flow of nitrogen and residence time of 8 minutesat 130 rpm. The material was then extruded through a 2.5 mm diameter dieand air cooled. The resulting blend was then pressed at 180° C. for 5minutes with minimal pressure to create a coherent film.

Sample Preparation

Blend films were loaded into a stainless steel dogbone die (gaugelength=16 mm, gauge width=3 mm, gauge thickness=0.6 mm) and pressed on aCarver press hot plate under ˜52 MPa at 180° C. for 5 minutes.Maintaining this pressure, the sample was cooled using water circulation(˜10° C./min). The samples were removed and trimmed with a razor blade.

Mechanical Testing

Mechanical studies were performed using a Zwick/Roell tensile testerelongated with a crosshead velocity of 16 mm/min. Tensile bars wereelongated until break and at least five tensile bars were tested foreach composite. Results were analyzed using Zwick/Roell testXpert II-v.3.5 software. Representative traces are presented in FIG. 12 andcompiled individual traces are presented in FIG. 19.

FIG. 12A shows the morphology obtained from a heterogeneous gradepolyolefin blend containing 70 wt % PE and 30 wt % iPP and FIG. 12Billustrates the consequences of adding 5 wt % of tetrablockPP₆₀PE₈₀PP₇₅PE₉₀ to this mixture. As described above, materials weremelt blended at 190° C. without block copolymer or with 1 wt % diblock,tetrablock, or 5 wt % tetrablock then compression molded into tensilespecimens at 180° C., and strained at a rate of 100%/min (FIG. 19). TEMimages of PE/iPP blends show droplet morphology (12A) without blockcopolymer and (12B) with 5 wt % tetrablock copolymer. Interfacialactivity of the block copolymer is evidenced by a reduction in theaverage droplet size from 2.2 μm to 0.55 μm with the addition of thetetrablock copolymer; similar results were obtained with otherarchitectures (see FIGS. 13-16).

Individually, pure iPP and PE display ductility and strain hardeningwhen pulled in tension at room temperature (FIG. 12C). Blending the twocomponents leads to a phase separated material and drastic reduction instrain at break (ε_(b)=12% versus 300% and 800% for iPP and PE,respectively). Addition of 5 wt % PP₆₀PE₈₀PP₇₅PE₉₀ raises ε_(b)=600%,due to the combined effects of interfacial adhesion, reduced particlesize, and efficient stress transfer between phases (FIG. 17). With just1% of this tetrablock copolymer ε_(b)=450%, while addition of 1 wt % ofthe corresponding diblock copolymer, PP₆₀PE₈₀, which leads to a modestimprovement, ε_(b)=90%. The low molecular weight tetrablock polymerPP₃₆PE₂₀PP₃₄PE₂₄ exhibited similar properties as did other PE:iPP ratios(FIG. 18).

The foregoing evidence the development of semi-crystalline PE/iPPmultiblock copolymers that can be synthesized with precise control overblock length and architecture. Embodiments of these macromolecules formstrong interfaces with commercial PE and iPP. Two molecular mechanismsare proposed to explain the molecular weight dependence of diblockcopolymer adhesion and the behavior of tetrablock copolymers withrelatively short blocks. The interfacial strength translates intocontrol over morphology and mechanical toughness in melt blends ofcommercial PE and iPP, blends that are otherwise brittle at a ratiofound in the municipal waste stream.

Multiblock Copolymers as Compatibilizers

To unambiguously examine the effect of block architecture oncompatibilization efficacy and interfacial activity, a single reactionwas carried out to synthesize the polymers shown in FIGS. 2A-C withremoval of large volumes (50 mL) after monomer consumption to provideadequate yields of each block for physical testing. In a proceduresimilar to the above general procedure, the cocatalyst mixture (30 μmol)was dissolved in toluene (200 mL) containing DIBAP (125 μmol of a 2.5Msolution) in a Fischer-Porter reactor, sealed, and removed from theglove box. The vessel was charged with propylene (2.0 g) and stirred for90 minutes in a water bath at 22° C. The reactor head was then attachedto a quick-connect valve routed to a nitrogen tank and vacuum pump. Thevessel was pressurized with nitrogen (1.5 atm) and evacuated undervacuum for 5 seconds before backfilling with nitrogen. This was repeatedfor a total of three times, then an aliquot (5 mL) was removed for GPCanalysis. The reaction vessel was then pressurized with ethylene (2.7atm) and stirred for 4 minutes prior to venting the ethylene atmosphere.Again the reactor head was attached to a vacuum/nitrogen source andevacuated/backfilled as before. The reaction was stirred for 40 minutesprior to removing a large aliquot (50 mL) via a syringe equipped with a10-gauge stainless steel needle and quenched by adding to MeOH (50 mL).The sample was vacuum filtered and dried at 60° C. under vacuum for 24h. Propylene was then condensed, stirred, evacuated/backfilled as above,followed by the removal of a large aliquot (50 mL). The final ethylenepolymerization was similarly carried out as above but quenched by theaddition of acidic MeOH (50 mL) instead of removing an aliquot. Theresulting tetrablock copolymer (entry 5, PP₆₀PE₈₀PP₇₅PE₉₀, 4.0 g) wasprojected to yield 8.5 g of polymer according to the removed volume. Nocorrections for monomer or polymer volume were made.

FIGS. 20-22 provide data relative to additional embodiments ofcompatibilized blends according to the invention. FIGS. 20A-C are chartssummarizing tensile properties of 70:30 (HDPE:iPP) blend embodimentswith the indicated multiblock copolymers added in 1 wt %, 0.5 wt %, and0.2 wt %. Three different tetrablocks with different molecular weightsand one hexablock were tested as compatibilizers. As illustrated,tensile properties were dramatically improved (>10 fold improvement instrain at break in all cases). Only a single representative trace isshown. FIGS. 21A-E are charts summarizing tensile properties of 70:30(HDPE:iPP) blend embodiments with the indicated multiblock copolymersadded in 1 wt %. Individual test samples are provided, in addition to arepresentative trace. FIGS. 22A-E are charts summarizing tensileproperties of 70:30 (HDPE:iPP) blend embodiments with the indicatedmultiblock copolymers added in 0.5 wt %. Individual test samples areprovided, in addition to a representative trace. FIGS. 23A-E are chartssummarizing tensile properties of 70:30 (HDPE:iPP) blend embodimentswith the indicated multiblock copolymers added in 0.2 wt %. Individualtest samples are provided, in addition to a representative trace. Thefigures demonstrate that, following addition of the inventivesemicrystalline multiblock copolymers, compatibility is undeniablyimproved.

CLAUSES

The following clauses describe certain non-limiting embodiments of theinvention.

Clause 1: A semicrystalline multiblock copolymer comprising alternatingblocks of semicrystalline isotactic polypropylene (iPP) andsemicrystalline polyethylene (PE), having a block arrangement accordingto formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n)   (I),whereinp is 0 or 1;m is 0 or 1;n is 0 or 1;the sum of p, m, and n is 1, 2, or 3; andthe sum of w, x, y, and z is greater than or equal to 40 kg/mol, withthe provisos that:

when m and n are 0, the sum of w and x is greater than or equal to 140kg/mol; and

when p and n are 0, the sum of y and x is greater than or equal to 140kg/mol.

Clause 2. The semicrystalline multiblock copolymer according to clause1, wherein the copolymer is a diblock copolymer having a blockarrangement according to formula (Ia):iPP_(w)PE_(x)   (Ia).

Clause 3. The semicrystalline multiblock copolymer according to clause 1or 2, wherein w is greater than 70 kg/mol, and x is greater than 70kg/mol.

Clause 4. The semicrystalline multiblock copolymer according to any oneof clauses 1-3, wherein at least one of w and x is greater than 100kg/mol.

Clause 5. The semicrystalline multiblock copolymer according to clause1, wherein the copolymer is a triblock copolymer having a blockarrangement according to formula (Ib) or formula (Ic):iPP_(w)PE_(x)iPP_(y)   (Ib)PE_(x)iPP_(y)PE_(z)   (Ic).

Clause 6. The semicrystalline multiblock copolymer according to clause5, wherein for formula (Ib), the sum of w, x, and y is greater than orequal to 70 kg/mol, and for formula (Ic), the sum of x, y, and z isgreater than or equal to 70 kg/mol.

Clause 7. The semicrystalline multiblock copolymer according to clause1, wherein the copolymer is a tetrablock copolymer having a blockarrangement according to formula (Id):iPP_(w)PE_(x)iPP_(y)PE_(z),   (Id).

Clause 8. The semicrystalline multiblock copolymer according to clause7, wherein w, x, y, and z are each independently greater than or equalto 15 kg/mol.

Clause 9. The semicrystalline multiblock copolymer according to clause7, wherein w, x, y, and z are each independently greater than or equalto 20 kg/mol.

Clause 10. The semicrystalline multiblock copolymer according to clause7, wherein w, x, y, and z are each independently selected from 10 to 150kg/mol.

Clause 11. The semicrystalline multiblock copolymer according to clause7, wherein the sum of w, x, y, and z is greater than or equal to 100kg/mol.

Clause 12. The semicrystalline multiblock copolymer according to clause1, having one or more blocks in addition to those of formula (I).

Clause 13. An adhesion layer comprising the semicrystalline multiblockcopolymer according to any one of clauses 1 to 12.

Clause 14. A multi-layer film or sheet comprising:

a first layer comprising polyethylene;

a second layer comprising polypropylene; and

an adhesion layer comprising the semicrystalline multiblock copolymeraccording to any one of clauses 1 to 12,

wherein the adhesion layer is disposed between the first layer and thesecond layer, and is in direct contact with the first layer and thesecond layer.

Clause 15. The multi-layer film or sheet according to clause 14, whereinthe polyethylene in the first layer is selected from the groupconsisting of: high density polyethylene (HDPE), linear low-densitypolyethylene (LLDPE), ultra high molecular weight polyethylene (UHMWPE),low density polyethylene (LDPE), very low density polyethylene (VLDPE),and polyethylene polyolefin block copolymer.

Clause 16. The multi-layer film or sheet according to clause 14 orclause 15, wherein the polypropylene in the second layer is selectedfrom the group consisting of: isotactic polypropylene (iPP), impactmodified polypropylene, polypropylene fibers, and biaxially orientedpolypropylene (BOPP).

Clause 17. A method of adhering a first layer comprising polyethyleneand a second layer comprising polypropylene, the method comprising:contacting the first layer and the second layer with an adhesivecomposition comprising a semicrystalline multiblock copolymer accordingto any one of clauses 1 to 12.

Clause 18. The method according to clause 17, wherein the adhesivecomposition is provided in the form of a film or sheet.

Clause 19. The method according to clause 17, wherein the adhesivecomposition is applied to the first layer or the second layer by:

-   -   blow molding;    -   electrospinning;    -   melt extruding;    -   injection molding;    -   application through sheer force; or    -   solvent casting.

Clause 20. A blended composition comprising polypropylene, polyethylene,and a semicrystalline multiblock copolymer according to any one ofclauses 1 to 12.

Clause 21. The composition according to clause 20, wherein thepolypropylene, polyethylene, and semicrystalline multiblock copolymerare present in a mixture having an average droplet diameter of less than1 μm.

Clause 22. The composition according to clause 20 or clause 21,comprising 0.2 to 5.0 wt % of the semicrystalline multiblock copolymer.

Clause 23. A process for forming the semicrystalline multiblockcopolymer according to any one of clauses 1-12, said process comprising:

-   -   in a reactor, in a non-polar, non-protic solvent, contacting        propylene monomers with a catalyst, thereby forming an iPP        block;    -   introducing ethylene monomers to the reactor, thereby forming a        PE block covalently bonded to the iPP block, thus forming a        semicrystalline diblock copolymer;    -   optionally, performing one or more additional steps of        introducing to the reactor propylene and/or ethylene monomers,        thus forming a semicrystalline multiblock copolymer having        additional blocks.

Clause 24. The process according to clause 23, wherein the solvent istoluene.

Clause 25. The process according to clause 23 or clause 24, wherein thecatalyst is the reaction product of a pyridylamidohafnium catalystprecursor and an activator.

Clause 26. The process according to clause 25, wherein thepyridylamidohafnium catalyst precursor is a compound of formula (II)

whereinR²¹ and R^(21′) are independently selected from H and methyl;R²² and R^(22′) are independently selected from isopropyl andtert-butyl;R²³ is selected from H, isopropyl and tert-butyl; andR²⁴ and R^(24′) are independently selected from C₁-C₄ linear or branchedalkyl and benzyl.

Clause 27. The process according to clause 26, wherein the activator isB(C₆F₅)₃ and the pyridylamidohafnium catalyst precursor is:

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has” and “having”), “include” (and any formof include, such as “includes” and “including”), “contain” (and any formcontain, such as “contains” and “containing”), and any other grammaticalvariant thereof, are open-ended linking verbs. As a result, a method ordevice that “comprises”, “has”, “includes” or “contains” one or moresteps or elements possesses those one or more steps or elements, but isnot limited to possessing only those one or more steps or elements.Likewise, a step of a method or an element of a composition or articlethat “comprises”, “has”, “includes” or “contains” one or more featurespossesses those one or more features, but is not limited to possessingonly those one or more features.

As used herein, the terms “comprising,” “has,” “including,”“containing,” and other grammatical variants thereof encompass the terms“consisting of” and “consisting essentially of.”

The phrase “consisting essentially of” or grammatical variants thereofwhen used herein are to be taken as specifying the stated features,integers, steps or components but do not preclude the addition of one ormore additional features, integers, steps, components or groups thereofbut only if the additional features, integers, steps, components orgroups thereof do not materially alter the basic and novelcharacteristics of the claimed composition, device or method.

All publications cited in this specification are herein incorporated byreference as if each individual publication were specifically andindividually indicated to be incorporated by reference herein as thoughfully set forth.

Subject matter incorporated by reference is not considered to be analternative to any claim limitations, unless otherwise explicitlyindicated.

Where one or more ranges are referred to throughout this specification,each range is intended to be a shorthand format for presentinginformation, where the range is understood to encompass each discretepoint within the range as if the same were fully set forth herein.

While several aspects and embodiments of the present invention have beendescribed and depicted herein, alternative aspects and embodiments maybe affected by those skilled in the art to accomplish the sameobjectives. Accordingly, this disclosure and the appended claims areintended to cover all such further and alternative aspects andembodiments as fall within the true spirit and scope of the invention.

The invention claimed is:
 1. A semicrystalline multiblock copolymercomprising alternating blocks of semicrystalline isotactic polypropylene(iPP) and semicrystalline polyethylene (PE), having a block arrangementaccording to formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n)   (I), wherein block(PE_(x)) consists of formula

block (PE_(z)) consists of formula

p is 0 or 1; m is 0 or 1; n is 0 or 1; the sum of p, m, and n is 1, 2,or 3; and the sum of w, x, y, and z is greater than or equal to 40kg/mol, with the provisos that: when m and n are 0, the sum of w and xis greater than or equal to 140 kg/mol; and when p and n are 0, the sumof y and x is greater than or equal to 140 kg/mol.
 2. Thesemicrystalline multiblock copolymer according to claim 1, wherein thecopolymer is a diblock copolymer having a block arrangement according toformula (Ia):iPP_(w)PE_(x)   (Ia).
 3. The semicrystalline multiblock copolymeraccording to claim 2, wherein w is greater than 70 kg/mol, and x isgreater than 70 kg/mol.
 4. The semicrystalline multiblock copolymeraccording to claim 3, wherein at least one of w and x is greater than100 kg/mol.
 5. The semicrystalline multiblock copolymer according toclaim 1, wherein the copolymer is a triblock copolymer having a blockarrangement according to formula (Ib) or formula (Ic):iPP_(w)PE_(x)iPP_(y)   (Ib)PE_(x)iPP_(y)PE_(z)   (Ic).
 6. The semicrystalline multiblock copolymeraccording to claim 5, wherein for formula (Ib), the sum of w, x, and yis greater than or equal to 70 kg/mol, and for formula (Ic), the sum ofx, y, and z is greater than or equal to 70 kg/mol.
 7. A semicrystallinemultiblock copolymer comprising alternating blocks of semicrystallineisotactic polypropylene (iPP) and semicrystalline polyethylene (PE),wherein the copolymer is a tetrablock copolymer having a blockarrangement according to formula (Id):iPP_(w)PE_(x)iPP_(y)PE_(z),   (Id), wherein the sum of w, x, y, and z isgreater than or equal to 40 kg/mol.
 8. The semicrystalline multiblockcopolymer according to claim 7, wherein w, x, y, and z are eachindependently greater than or equal to 15 kg/mol.
 9. The semicrystallinemultiblock copolymer according to claim 7, wherein the sum of w, x, y,and z is greater than or equal to 100 kg/mol.
 10. A semicrystallinemultiblock copolymer comprising alternating blocks of semicrystallineisotactic polypropylene (iPP) and semicrystalline polyethylene (PE),having a block arrangement according to formula (I):(iPP_(w))_(p)(PE_(x))(iPP_(y))_(m)(PE_(z))_(n)   (I), wherein p is 0 or1; m is 0 or 1; n is 0 or 1; the sum of p, m, and n is 1, 2, or 3; andthe sum of w, x, y, and z is greater than or equal to 40 kg/mol, withthe provisos that: when m and n are 0, the sum of w and x is greaterthan or equal to 140 kg/mol; and when p and n are 0, the sum of y and xis greater than or equal to 140 kg/mol, and wherein said semicrystallinemultiblock copolymer includes one or more blocks in addition to those offormula (I).
 11. An adhesion layer comprising the semicrystallinemultiblock copolymer according to claim
 1. 12. A multi-layer film orsheet comprising: a first layer comprising polyethylene; a second layercomprising polypropylene; and an adhesion layer comprising thesemicrystalline multiblock copolymer according to claim 1, wherein theadhesion layer is disposed between the first layer and the second layer,and is in direct contact with the first layer and the second layer. 13.The multi-layer film or sheet according to claim 12, wherein thepolyethylene in the first layer is selected from the group consistingof: high density polyethylene (HDPE), linear low-density polyethylene(LLDPE), ultra high molecular weight polyethylene (UHMWPE), low densitypolyethylene (LDPE), very low density polyethylene (VLDPE), andpolyethylene polyolefin block copolymer; and the polypropylene in thesecond layer is selected from the group consisting of: isotacticpolypropylene (iPP), impact modified polypropylene, polypropylenefibers, and biaxially oriented polypropylene (BOPP).
 14. A method ofadhering a first layer comprising polyethylene and a second layercomprising polypropylene, the method comprising: contacting the firstlayer and the second layer with an adhesive composition comprising asemicrystalline multiblock copolymer according to claim
 1. 15. Themethod according to claim 14, wherein the adhesive composition isprovided in the form of a film or sheet and the adhesive composition isapplied to the first layer or the second layer by: blow molding;electrospinning; melt extruding; injection molding; application throughsheer force; or solvent casting.
 16. A blended composition comprisingpolypropylene, polyethylene, and a semicrystalline multiblock copolymeraccording to claim
 1. 17. The composition according to claim 16,comprising 0.2 to 5.0 wt % of the semicrystalline multiblock copolymer.18. A process for forming the semicrystalline multiblock copolymeraccording to claim 1, said process comprising: in a reactor, in anon-polar, non-protic solvent, contacting propylene monomers with acatalyst, thereby forming an iPP block; introducing ethylene monomers tothe reactor, thereby forming a PE block covalently bonded to the iPPblock, thus forming a semicrystalline diblock copolymer; optionally,performing one or more additional steps of introducing to the reactorpropylene and/or ethylene monomers, thus forming a semicrystallinemultiblock copolymer having additional blocks.
 19. The process accordingto claim 18, wherein the catalyst is the reaction product of apyridylamidohafnium catalyst precursor and an activator.
 20. The processaccording to claim 19, wherein the pyridylamidohafnium catalystprecursor is a compound of formula (II)

wherein R²¹ and R^(21′) are independently selected from H and methyl;R²² and R^(22′) are independently selected from isopropyl andtert-butyl; R²³ is selected from H, isopropyl and tert-butyl; and R²⁴and R^(24′) are independently selected from C₁-C₄ linear or branchedalkyl and benzyl.
 21. The process according to claim 20, wherein theactivator is B(C₆F₅)₃ and the pyridylamidohafnium catalyst precursor is:


22. The semicrystalline multiblock copolymer according to claim 1,wherein the sum of p, m, and n is 2 or
 3. 23. The semicrystallinemultiblock copolymer according to claim 1, wherein the semicrystallinemultiblock copolymer: comprises less than 1 wt % ethylene-co-propylenesegments, based on the weight of the multiblock copolymer; and/or has anNMR spectrum on which ethylene-co-propylene segments are not detectable.